Quote:

I did have one correction, with E90 the stoich A/F would be slightly lower than E85. A rough check:
Stoich Ethanol 9.0
Stoich Gasoline 14.7

E85: 0.85(9.0) + 0.15(14.7) = 7.65 + 2.21 = 9.8
E90: 0.90(9.0) + 0.10(14.7) = 8.10 + 1.47 = 9.6

Published numbers for E85 I have seen were 9.76. And I don't know if the stoich for the Maximal is different than 14.7 (maybe 14.5).

So, for max (safe) power, I would want to see richer than stoich, in the range I mentioned. And perhaps the dyno operator just has seen max power close to stoich on gas (but I would want to be richer to be safe). Use the cooling effect of the ethanol and put more fuel to it. But that may only be a secondary issue with the rings, not the prime cause.

Good luck.


I may have too much cylinder pressure as a result of the cam having 112 lobe center. I am staying away from the ethanol on this engine, and staying with race gas to be safe. But on my next build, I think I'll try to build one specifically for the E85 and match the camshaft specs to that combo. Do you have any idea about what effect mixing leaded race gas with ethanol has? Some people on this thread say it doesn't raise the octane level like you would expect, and that would account for the detonation.